/*

 * Licensed to the Apache Software Foundation (ASF) under one

 * or more contributor license agreements.  See the NOTICE file

 * distributed with this work for additional information

 * regarding copyright ownership.  The ASF licenses this file

 * to you under the Apache License, Version 2.0 (the

 * "License"); you may not use this file except in compliance

 * with the License.  You may obtain a copy of the License at

 *

 *     http://www.apache.org/licenses/LICENSE-2.0

 *

 * Unless required by applicable law or agreed to in writing, software

 * distributed under the License is distributed on an "AS IS" BASIS,

 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.

 * See the License for the specific language governing permissions and

 * limitations under the License.

 */

package com.bff.gaia.unified.sdk.coders;



import com.bff.gaia.unified.sdk.values.TypeDescriptor;



import java.io.*;



/** A {@link DoubleCoder} encodes {@link Double} values in 8 bytes using Java serialization. */

public class DoubleCoder extends AtomicCoder<Double> {



  public static DoubleCoder of() {

    return INSTANCE;

  }



  /////////////////////////////////////////////////////////////////////////////



  private static final DoubleCoder INSTANCE = new DoubleCoder();

  private static final TypeDescriptor<Double> TYPE_DESCRIPTOR = new TypeDescriptor<Double>() {};



  private DoubleCoder() {}



  @Override

  public void encode(Double value, OutputStream outStream) throws IOException, CoderException {

    if (value == null) {

      throw new CoderException("cannot encode a null Double");

    }

    new DataOutputStream(outStream).writeDouble(value);

  }



  @Override

  public Double decode(InputStream inStream) throws IOException, CoderException {

    try {

      return new DataInputStream(inStream).readDouble();

    } catch (EOFException | UTFDataFormatException exn) {

      // These exceptions correspond to decoding problems, so change

      // what kind of exception they're branded as.

      throw new CoderException(exn);

    }

  }



  /**

   * {@inheritDoc}

   *

   * @throws NonDeterministicException always. Floating-point operations are not guaranteed to be

   *     deterministic, even if the storage format might be, so floating point representations are

   *     not recommended for use in operations that require deterministic inputs.

   */

  @Override

  public void verifyDeterministic() throws NonDeterministicException {

    throw new NonDeterministicException(

        this, "Floating point encodings are not guaranteed to be deterministic.");

  }



  /**

   * {@inheritDoc}

   *

   * @return {@code true}. This coder is injective.

   */

  @Override

  public boolean consistentWithEquals() {

    return true;

  }



  /**

   * {@inheritDoc}

   *

   * @return {@code true}. {@link DoubleCoder#getEncodedElementByteSize} returns a constant.

   */

  @Override

  public boolean isRegisterByteSizeObserverCheap(Double value) {

    return true;

  }



  @Override

  public TypeDescriptor<Double> getEncodedTypeDescriptor() {

    return TYPE_DESCRIPTOR;

  }



  /**

   * {@inheritDoc}

   *

   * @return {@code 8}, the byte size of a {@link Double} encoded using Java serialization.

   */

  @Override

  protected long getEncodedElementByteSize(Double value) throws Exception {

    if (value == null) {

      throw new CoderException("cannot encode a null Double");

    }

    return 8;

  }

}